Giorgio Sangiovanni (Universitaet Wuerzburg)

Jeudi 31 mai, amphi Urbain à 14H00

Local magnetic moments in iron and nickel at ambient and Earth’s core conditions

Some Bravais lattices have a particular geometry that can slow down the motion of Bloch electrons by pre-localization due to the band-structure properties. Another known source of electronic localization in solids is the Coulomb repulsion in partially filled d or f orbitals, which leads to the formation of local magnetic moments. The combination of these two effects is usually considered of little relevance to strongly correlated materials. Here we show that it represents, instead, the underlying physical mechanism in two of the most important fer- romagnets : nickel and iron. In nickel, the van Hove singularity has an unexpected impact on the magnetism. As a result, the electron–electron scattering rate is linear in temperature, in violation of the conventional Landau theory of metals. This is true even at Earth’s core pressures, at which iron is instead a good Fermi liquid. The importance of nickel in models of geomagnetism may have therefore to be reconsidered.

Nature Communications 8, 16062 (2017)
DOI : 10.1038/ncomms16062

Haut de page

À lire aussi...

Nicolas Ubrig,Department of Quantum Matter Physics, University of Geneva

Nicolas Ubrig, jeudi 24 mai 2018, amphi Urbain à14h00 Valley and spin physics in atomically thin van der Waals materials The discovery of graphene (...) 

> Lire la suite...

Xiaokang Li,Wuhan National High Magnetic Field Center and School of Physics, Huazhong University of Science and Technology,China

jeudi 6 décembre à 14h00 Amphi Schutzenberger Anomalous Transverse Transport in non-collinear antiferromagnets Mn3X(X=Sn, Ge)] Wuhan National (...) 

> Lire la suite...